Harbor Marina



423 Three Mile Harbor
Hog Creek Road

East Hampton, NY 11937

Tel 631-324-5666

Fax 631-324-3366



Gas and Diesel Fuel Dock


Valvetect logoThe Harbor Marina fuel dock is located at the first marina inside the channel entrance of Three Mile Harbor, less than 10 minutes from the open waters of Gardiner's Bay. Harbor Marina has been a proud supplier of the high quality ValvTect marine grade gasoline and diesel fuels since the mid-1980's and sells a 89-octane ValvTect gasoline and the marine grade Ultra-low sulfur diesel . Both fuels contain ValvTect branded additives that are specifically suited for all engines in the marine environment. Mercury 4-Stroke Verado Outboards over 250HP are recommended to use Gasoline rated at 91-Octane and these engine owners can find ValvTect Octane Boost in the Harbor Marina Ship's Store.

To access the fuel dock, boaters should clear the green can (#8) in front of the marina, leaving it to their north side (see photo below). Recent soundings show over 7' of water at low tide both in the approach to the fuel dock and beyond the dock if a wide turning area is required. The tidal range is 3'. Click here for a link to the current tides in Three Mile Harbor. Harbor Marina staff will be glad to assist your approach during the boating season and are available on Channel VHF 9 or by prior arrangement at 631-324-5666, ext. 1.

Shoreside, boaters will find clean restrooms, a retail store with a full line of marine products and accessories, watersport items, snacks, drinks, ice cream, gifts, sundries, and parts for most marine engines and systems. Click here for a link to our engine dealerships and here to contact the Service Department.



Three Mile Harbor (LAT. 41° 02.20'N, LON 72° 11.35'W)

Three Mile Harbor fuel dock location (LAT. 41° 01.74'N, LON. 72° 10.82'W)


View Fuel Dock in a larger map


Gas and Diesel Fuel Dock


Fuel Dock



ValvTect Octane Boost

ValvTect Octane Boost is specially formulated for marine and other off-road engines that require higher octane gasoline. ValvTect Octane Boost raises gasoline octane up to two full numbers (20 points) and cleans up injector and fuel system deposits to help engines develop full power and performance.

  • Adds up to 2 full octane numbers
  • Provides maximum allowable octane boost
  • Cleans injectors and fuel systems Boosts engine power and performance
  • 32 oz. treats 140 gallons gas.

Weather Conditions . . .

go to noaa
check local weather
check tide table
check wind


Seacoast Enterprises Associates, Inc.
423 Three Mile Harbor Hog Creek Road
East Hampton, NY 11937
Phone: 631-324-5666
Email: info@sea-incorp.com
Google Map Directions


Harbor Marina
Halseys Marina
Gardiners Marina